This invention relates generally to a creel used to hold yarn packages to be consumed by yarn processing machines, and more specifically to a machine mounted overhead creel carrying bobbins of yarn to be used in conjunction with a ring twister.
Ring twisters are generally used in the textile industry to impart twist in yarn taken off a first yarn package and to repackage the yarn on a second yarn package, or bobbin. The second package, or twister bobbin, is held by the twister machine in a vertical orientation on a twister spindle below twister pull rolls and the yarn is fed from the first yarn packages into the machine through the pull rolls generally from overhead. In a typical ring twister, there are approximately 50 spindles mounted on each of two sides of the twister for a total of 100 spindles, and twister bobbins. A separate bank of twister pull rolls feeds yarn to the twister bobbins on each side of the machine. The first packages, which may include yarn wrapped on, for example, bobbins or tubes, are held by a structure known as a creel. For purposes of this disclosure, the first yarn package is hereinafter referred to as a creel bobbin.
It is generally the function of a twisting machine to twist together two or three plies of yarn to form a single yarn wound onto each twister bobbin. A creel must carry at least one creel bobbin for each ply twisted onto each twister bobbin. For simplicity, the following specification shall be in terms of the production of two ply yarn, but it will be understood that the invention may be embodied in the production of yarn of more than two plies (or only one end). Therefore, for each two ply yarn produced on one twister bobbin, yarn must be fed to the twister machine from two separate creel bobbins. For many years, the two yarn supply bobbins were positioned on a yarn stand or creel mounted above the yarn processing machine, one supply bobbin for each ply. When one creel bobbin ran out of yarn, the spindle had to be disengaged and the empty bobbin replaced by a full one. Therefore, the ring twister spindles were constantly being disengaged to replace bobbins.
In an effort to minimize the number of spindle shut downs, it has become common practice in the trade to tie or splice a reserve creel bobbin to each of the original, or supply, creel bobbins. The lead end of the reserve bobbin is tied to the tail end of the supply bobbin in order that, as the supply bobbin runs out of yarn, the reserve bobbin immediately begins feeding yarn to the twister. While the reserve bobbin is feeding yarn, the original supply bobbin is replaced by yet another full creel bobbin and the lead end of this third creel bobbin is spliced to the tail end of the reserve bobbin. When reserve creel bobbins are utilized in the production of two-ply yarn, the creel must carry four creel bobbins for each twister bobbin.
As the number of yarn supply bobbins carried by the creel increased, it became difficult to accommodate the necessary number of bobbins on a machine mounted creel without positioning some of the bobbins high above the yarn processing machine where ready access was impaired. Therefore, creel design has centered around the need for a creel which can hold the great number of creel bobbins necessary and keep these bobbins in a readily accessible position.
Typically floor standing side creels have been developed by the industry to hold a large number of bobbins in close proximity to the floor for easy access. See for example U.S. Pat. No. 3,674,223. However, the need for increased production of yarns has pressed manufacturers to purchase more processing machines and to make room in their plants for these new machines. In an effort to find added space for the new machines, new ways have been sought to get the creel off the floor and back above the machine.
The machine mounted creels must provide for easy access to the creel bobbins by an operator in order that the creel can be loaded and unloaded with reserve bobbins and spliced without affecting the continued operation of the machine. An operator must get to every station along the twister machine, that is, one station for each of the approximately 100 spindles, before the yarn runs out, and unload, load and splice each of the empty creel bobbins. If the operator moves too slow and misses one station, that spindle must be shut down and the yarn rethreaded, thus lessening the efficiency of the machine.
While loading and unloading the creel bobbins, it is important that the flow of yarn from the creel bobbins to the twister machine not be interrupted and furthermore, that the length of the yarn moving to the ring twister not be substantially changed. If the yarn is allowed to slacken or stretch by any substantial amount, yarn loops or breaks can result in the yarn feeding to the twister bobbins.
It is, therefore, desirable to provide a creel which an be quickly serviced with a minimum of energy expended by the operator while maintaining continuous satisfactory operation of the yarn processing machine.